When adding shared memory, memories owned by the module were added to a
`owned_memories` array placed immediately after the `defined_memories`
array. When checking the size of each array with `region_sizes`, the
size of `defined_memories` and `owned_memories` were checked in this
order. But `region_sizes` is iterating through the fields in the reverse
order. This change reverses the field order to fix the associated fuzz
bug.
0dcda643ea